Targeted disruption of Plasmodium falciparum cysteine protease, falcipain 1, reduces oocyst production, not erythrocytic stage growth
Details
Publication Year 2004-07,Volume 53,Issue #1,Page 243-250
Journal Title
MOLECULAR MICROBIOLOGY
Publication Type
Journal Article
Abstract
Cysteine proteases are currently targets for drug development in a number of parasitic diseases, including malaria. In Plasmodium falciparum, the parasite responsible for the most virulent form of human malaria, there are four members of the cathepsin L-like family of cysteine proteases. Three of these (falcipains 2A, 2B and 3) are thought to be primarily involved in haemoglobin digestion, whereas falcipain 1 has recently been linked to erythrocyte invasion. Neither their expression nor their role in P. falciparum gametocytogenesis, which is required for malaria transmission, has been evaluated. In this study, RNA transcripts for the falcipain family members were identified as the parasite developed through all five stages of gametocytogenesis. Falcipain 1 transcript was upregulated in gametocytes, while levels of falcipain 2A/2B decreased in late-stage gametocytes and gametes. To evaluate the function of falcipain 1, the gene was disrupted, and clones from independent transformations were isolated. The asexual growth of the falcipain 1 minus clones was not overtly affected, and they produced morphologically normal gametocytes and gametes. However, when falcipain 1 minus parasites were fed to a mosquito, oocyst production was reduced by 70-90%, suggesting an important role for falcipain 1 during parasite development in the mosquito midgut.
Publisher
BLACKWELL PUBLISHING LTD
Keywords
MALARIA PARASITES; HOST ERYTHROCYTE; INVASION; PLASMIDS; GENE; GAMETOCYTAEMIA; PYRIMETHAMINE; PROTEINASE; EXPRESSION
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Creation Date: 2004-07-01 12:00:00
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